Recently, due to the wide spread use of the Internet, it has been common to provide information converted to a digital form. Typical examples of digitalized geographic information may include online map services, car navigation systems, etc. As such, one of benefits of the digitalized geographic information is to provide a variety of convenient functions for users by combining them with user interfaces capable of providing a retrieval function. Further, changes in geographic information may be easily updated through remote updating services, etc., so that, in the aspect of latest geographic information, such digital data may be predominant over conventional printed materials.
However, it has been conventionally common for service providers to combine digital maps generated by the combination of simple symbols with search interfaces and provide digital geographic information, but since there are apparent differences between information of areas displayed on the digital map and real information of the areas, it is difficult to identify the real information of the areas from the digital map.
As an attempt to solve such a problem, US Laid-Open Publication No. 2008-143727 dated Jun. 19, 2008 discloses a technology for providing a panoramic image(s) relating to a certain place such as a bystreet, a road, etc. appearing on the digital map and, if a user selects a specific pixel with an arrow, etc. on the panoramic image, offering data of a different panoramic image corresponding to a place shown at the specific pixel. Accordingly, users may identify real information of the certain place on the digital map and inquire for another panoramic image which expresses geographic information at the certain place shown on the panoramic image the user is now inquiring for in a more detail through a link between panoramic images.
In addition, a technology which performs visual search by using a panoramic image(s) has been introduced. According to the technology, by referring to a queried image inputted by a user, it may retrieve an appropriate panoramic image including what is similar to the object included in the queried image among multiple panoramic images and provide the appropriate panoramic image to the user.
However, according to the technology of performing visual search by using the panoramic images, since the image matching operations for comparing the queried image with all the panoramic images stored in the database must be performed, the execution time for the image matching process becomes more increased and degrees of precision of the image matching process become lower.